diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3c4559de..32e14bd1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ Unreleased
 - Adjusted program to use Rust Edition 2021
 - Updated minimum supported Rust version to `1.56.0`
 - Bumped `anyhow` dependency to `1.0.89`
+- Bumped `base32` dependency to `0.5.1`
 - Bumped `directories` dependency to `5.0.1`
 - Bumped `libc` dependency to `0.2.159`
 - Bumped `serde` dependency to `1.0.147`
diff --git a/Cargo.lock b/Cargo.lock
index 933d5fc1..ad935c89 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -25,9 +25,9 @@ checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 
 [[package]]
 name = "base32"
-version = "0.4.0"
+version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "23ce669cd6c8588f79e15cf450314f9638f967fc5770ff1c7c1deb0925ea7cfa"
+checksum = "022dfe9eb35f19ebbcb51e0b40a5ab759f46ad60cadf7297e0bd085afb50e076"
 
 [[package]]
 name = "bitflags"
diff --git a/Cargo.toml b/Cargo.toml
index 933aee3b..e6f89301 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -42,7 +42,7 @@ incremental = false
 version = "1.0"
 
 [dependencies.base32]
-version = "0.4.0"
+version = "0.5.1"
 
 [dependencies.directories]
 version = "5"
diff --git a/src/commands.rs b/src/commands.rs
index ab6bcc38..9ef69153 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -887,8 +887,10 @@ fn prepare_ascii_secret(secret: &str) -> anyhow::Result<String> {
 /// Prepare a base32 secret string for libnitrokey.
 fn prepare_base32_secret(secret: &str) -> anyhow::Result<String> {
   // Some sites display the base32 secret in groups separated by spaces, we want to ignore them.
-  let secret = secret.replace(' ', "");
-  base32::decode(base32::Alphabet::RFC4648 { padding: false }, &secret)
+  let mut secret = secret.replace(' ', "");
+  let () = secret.make_ascii_lowercase();
+
+  base32::decode(base32::Alphabet::Rfc4648Lower { padding: false }, &secret)
     .map(|vec| format_bytes(&vec))
     .context("Failed to parse base32 secret")
 }